Many 3-substituted cephalosporin compounds having a substituted oxyimino moiety in the 7-position substituent are known as described in, for example, GB Pat. No. 2098216, EP Pat. No. 74645, etc. Some compounds of the invention of the former patent have a characteristic in that the substituent of the 3-position is a pyridinio group which may be substituted by an alkyl group or an alkoxy group, and the oxyimino moiety at the 7-position is substituted by a C.sub.1 to C.sub.6 alkyl group, etc.; and the invention of the latter patent has a characteristic in that the substituent at the 3-position is a pyridinio group which is substituted by an amino group or a protected amino group, and the oxyimino moiety at the 7-position has a lower aliphatic hydrocarbon group which may be substituted by some group(s).
On the other hand, the present invention provides cephalosporin compounds having a chemical-structural characteristic in that the substituent at the 3-position is a substituted pyridinio group.